Multilayer coated ceramic flame retardant as well as preparation method and application thereof

Abstract

The invention relates to the field of flame retardants, and particularly discloses a multi-layer coated ceramic flame retardant as well as a preparation method and application thereof. The invention relates to a preparation method of a multilayer coated ceramic flame retardant, which comprises the following steps: (1) adding alkyl phosphate diethanolamine salt into water, and uniformly stirring to prepare a mixed solution; (2) adding wollastonite fibers into the mixed solution, and uniformly stirring to obtain a blended solution; (3) filtering, drying and grinding the blended solution to obtain mixed powder; and (4) adding the mixed powder into dipropylene glycol dimethyl ether, uniformly stirring, adding fatty alcohol-polyoxyethylene ether phosphate and boron phosphide, uniformly stirring, filtering, drying, and crushing to obtain the multilayer coated ceramic flame retardant. The multilayer coated ceramic flame retardant can be used for wire and cable materials, and has the advantages of good flame retardant property and high ceramic body strength after ceramization; in addition, the preparation method provided by the invention has the advantages that the flame retardant is easy to disperse and the flame retardant property is outstanding.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flame retardants, more particularly, it relates to a multi-layer coated ceramicized flame retardant and a preparation method and application thereof. BACKGROUND

[0003] The ceramicized silicone rubber material is a new type of high polymer composite material, which is easy to process and has low production cost, is non-toxic and odorless at room temperature, has good softness and elasticity, and can be converted into a ceramic body with certain bending strength and compressive strength when subjected to open flame burning or high temperature environment, thereby preventing the flame from spreading to the inside of the polymer and to the surrounding environment, so as to protect the burned object from damage. The longer the ablation time and the higher the temperature, the harder the shell.

[0004] With regard to the above-mentioned related technology, the inventors have found that the ceramicized silicone rubber material still has some problems when used as a cable fixing head. First, the temperature of the ceramicization reaction is too high, generally above 650 DEG C, and the silicone rubber matrix will be pyrolyzed and powdered above 200 DEG C. If the environmental temperature is between 200 DEG C and 650 DEG C, the silicone rubber matrix has already degraded, and the ceramicization reaction has not yet occurred, greatly reducing the self-supporting property and strength of the silicone rubber material in the ceramicization process and affecting use. Second, the ceramic body converted after the ceramicization of the ceramicized silicone rubber is hard and has self-supporting property, but the ceramic strength is low, and the structure of the formed ceramic protective layer is poor in integrity, making it difficult to play the best protective role. SUMMARY

[0005] In order to reduce the ceramicization temperature of the ceramicized flame retardant material, increase the ceramicization integrity and ceramicization strength, the present application provides a multi-layer coated ceramicized flame retardant and a preparation method and application thereof.

[0006] In the first aspect, the present application provides a preparation method of a multi-layer coated ceramicized flame retardant, which adopts the following technical scheme: A preparation method of a multi-layer coated ceramicized flame retardant, comprising the following steps: (1) adding alkyl phosphate diethanolamine salt into water, stirring uniformly to prepare a mixed solution; (2) adding wollastonite fiber into the mixed solution, stirring uniformly to prepare a blended solution; (3) filtering, drying and grinding the blended solution to prepare a mixed powder; (4) adding the mixed powder into dipropylene glycol dimethyl ether, stirring uniformly, then adding fatty alcohol polyoxyethylene ether phosphate and boron phosphide, stirring uniformly, then filtering, drying and crushing to prepare a multi-layer coated ceramicized flame retardant.

[0007] By adopting the technical scheme, the alkyl phosphate diethanolamine salt is first dissolved in water to form a mixed solution, the mixed solution is mixed with the wollastonite fiber, the alkyl phosphate diethanolamine salt is a surfactant and can be coated on the surface of the wollastonite fiber, then the mixed powder is coated with fatty alcohol polyoxyethylene ether phosphate and boron phosphide, on the one hand, a multi-layer coating structure can be formed, on the other hand, the alkyl phosphate diethanolamine salt and the fatty alcohol polyoxyethylene ether phosphate can be decomposed into a compound containing phosphorus and oxygen at high temperature, and react with the wollastonite fiber and the boron phosphide at high temperature, so that the entire flame-retardant powder gradually fuses and densifies to form a ceramic layer with a more complete structure, and the higher the temperature, the easier the reaction, the higher the strength of the ceramic layer formed, and the last coating of the fatty alcohol polyoxyethylene ether phosphate makes the surface of the mixed powder hydrophobic, which can be more easily combined with rubber and has better reinforcing effect.

[0008] Optionally, the mass ratio of the alkyl phosphate diethanolamine salt to water is 20-30:100.

[0009] By adopting the above technical scheme, the water and the alkyl phosphate diethanolamine salt in the above amount ratio can make the alkyl phosphate diethanolamine salt fully dissolved to form a mixed solution which is easy to coat on the wollastonite fiber.

[0010] Optionally, the mass ratio of the fatty alcohol polyoxyethylene ether phosphate to dipropylene glycol dimethyl ether is 100:0.5-2.

[0011] By adopting the above technical scheme, the fatty alcohol polyoxyethylene ether phosphate mixed with dipropylene glycol dimethyl ether forms a solution with appropriate concentration, which can reduce the hydrophilicity of the alkyl phosphate diethanolamine salt coated on the surface of the wollastonite fiber, so that the multi-layer coated ceramic flame retardant is more easily dispersed in the rubber, achieving better reinforcing effect.

[0012] Optionally, the stirring temperature in step (1) is 90-100℃, and the stirring time is 10-30min.

[0013] By adopting the above technical scheme, the stirring temperature and time can make the alkyl phosphate diethanolamine salt fully dissolved to form a mixed solution with appropriate concentration.

[0014] Optionally, the stirring temperature in step (2) is 90-100℃, and the stirring time is 20-40min.

[0015] By adopting the above technical scheme, the uniform stirring and time can make the alkyl phosphate diethanolamine salt be more uniformly coated on the wollastonite fiber, and when the alkyl phosphate diethanolamine salt uniformly coated on the wollastonite fiber is decomposed at high temperature, a relatively dense ceramic layer can be formed on the wollastonite fiber, improving the flame-retardant effect.

[0016] In a second aspect, the application provides a preparation method of the multi-layer coated ceramicized flame retardant, which adopts the technical scheme as follows: The multi-layer coated ceramicized flame retardant is prepared by the preparation method of the multi-layer coated ceramicized flame retardant, and includes the following raw materials in percentage by weight: wollastonite fiber 16-30%, boron phosphide 65-81%, alkyl phosphate diethanolamine salt 2.75-4.25%, and fatty alcohol polyoxyethylene ether phosphate 0.25-0.75%.

[0017] By adopting the above technical scheme, the wollastonite fiber is an inorganic acicular mineral, which has the characteristics of chemical corrosion resistance, good thermal stability and dimensional stability, and a phase transition temperature of 1155-1300℃, and a very small volume change during phase transition, which is beneficial to rapid preheating and cooling and rapid ceramicization. The boron phosphide is a sphalerite-type crystal structure with a melting point of 1100℃, which acts as a framework during the ceramicization process of the wollastonite fiber and is interlaced, intertwined and overlapped with the wollastonite fiber, thereby forming a more solid ceramic layer than general spherical particles. The unique hard short fiber structure of the wollastonite fiber can play a good stress conducting and supporting role, thereby improving the bending strength and impact resistance of the electric wire and cable. Moreover, when a small crack occurs, the interaction between the fibrous particles will cause the flame-retardant powder around the crack to move rapidly to supplement, thereby repairing the small crack, and further making the electric wire and cable have good hardness, wear resistance, flame retardance, fire resistance and corrosion resistance. In addition, the impact strength and bending strength of the material can also be improved. The alkyl phosphate diethanolamine can decompose at high temperature to form a compound containing phosphorus and oxygen, and then realize high-temperature sintering with the wollastonite fiber and the boron phosphide at high temperature, so that the flame-retardant powder gradually fuses and densifies to form a ceramic layer with a more compact structure. The fatty alcohol polyoxyethylene ether phosphate improves the dispersibility of the wollastonite fiber, the boron phosphide and the alkyl phosphate diethanolamine salt with the electric wire and cable material by improving the surface chemical bond, so that the multi-layer coated ceramicized flame retardant is more easily combined with the rubber to achieve a good reinforcing effect. Moreover, after pyrolysis, the fatty alcohol polyoxyethylene ether phosphate forms a compound containing phosphorus and oxygen, such as metaphosphoric acid, which can sinter with the wollastonite and the boron phosphide at high temperature to form a ceramic layer with high strength and good density, thereby improving the flame-retardant effect.

[0018] Optionally, the preparation method includes the following raw materials in percentage by weight: wollastonite fiber 24%, boron phosphide 72%, alkyl phosphate diethanolamine salt 3.5%, and fatty alcohol polyoxyethylene ether phosphate 0.5%.

[0019] By adopting the above technical scheme, the mass percentage of each raw material in the above multi-layer coated ceramicized flame retardant is more accurate, and when added to the electric wire and cable, it can rapidly form a ceramic layer with high strength and good density at low temperature, thereby achieving a good flame-retardant effect.

[0020] Optionally, the aspect ratio of the wollastonite fiber is 2-20:1.

[0021] By adopting the above technical scheme, the wollastonite fiber with the above length-diameter ratio has a relatively suitable specific surface area, and the wollastonite fiber forms an interwoven network structure in the process of ceramic formation, thereby improving the ceramic strength; if the length-diameter ratio is relatively small, the formation of the network structure will be affected, and the final ceramic strength is poor; if the length-diameter ratio is relatively large, the specific surface area is relatively large, which is not conducive to dispersion, and will also lead to a decrease in the ceramic strength.

[0022] In a third aspect, the application provides an application of the multilayer coated ceramicized flame retardant prepared by the multilayer coated ceramicized flame retardant preparation method to an electric wire and cable, and the following technical scheme is adopted: The application of the multilayer coated ceramicized flame retardant prepared by the multilayer coated ceramicized flame retardant preparation method to an electric wire and cable, and the electric wire and cable comprises the following raw materials in parts by weight: ethylene-propylene rubber 100 parts, multilayer coated ceramicized flame retardant 150-300 parts, and DCP 1-3 parts.

[0023] By adopting the above technical scheme, 150-300 parts by weight of the multilayer coated ceramicized flame retardant is added to 100 parts by weight of the ethylene-propylene rubber, the ceramic flame retardant powder can form a high-strength, complete-structure and dense ceramic layer at about 400 DEG C, the ceramic layer can withstand a high temperature of 1500 DEG C, the flame retardant effect is excellent, and the electric wire and cable has high tensile strength, large elongation and large oxygen index, and good flame retardant effect.

[0024] Optionally, the ethylene-propylene rubber is a terpolymer ethylene-propylene rubber, and the ethylene content is 58-66%.

[0025] By adopting the above technical scheme, the terpolymer ethylene-propylene rubber is a copolymer of ethylene, propylene and a small amount of non-conjugated diene, and is a kind of ethylene-propylene rubber; the ethylene content directly affects the heat resistance, physical properties and aging resistance of the electric wire and cable; the terpolymer ethylene-propylene rubber with an ethylene content of 58-66% can make the electric wire and cable have high tensile strength and tear strength, and large hardness and resilience of vulcanized rubber.

[0026] In summary, the application has the following beneficial effects: 1. The ceramicized flame retardant is prepared by coating alkyl phosphate diethanolamine salt, wollastonite fiber and boron phosphide, and fatty alcohol polyoxyethylene ether phosphate in multiple layers, the fatty alcohol polyoxyethylene ether phosphate can improve the dispersibility and bonding force of the ceramicized flame retardant and rubber, improve the reinforcing effect, the alkyl phosphate diethanolamine salt and fatty alcohol polyoxyethylene ether phosphate decompose at 400-500 DEG C to form phosphorus-containing compounds, which react with the wollastonite fiber and boron phosphide at high temperature, so that the flame retardant gradually fuses and densifies, therefore, the multilayer coated ceramicized flame retardant has a low ceramic formation temperature, the ceramic layer has a complete structure and high strength, has high heat resistance, and has good flame retardant performance.

[0027] 2. Preferably, 150-300 parts of the multi-layer coated ceramicized flame retardant is added to 100 parts of ethylene-propylene rubber in the application, which can make the tensile strength of the wire and cable high, the mechanical strength good, and the flame retardancy excellent, and the smoke density small.

[0028] 3. The preparation method of the multi-layer coated ceramicized flame retardant of the application is simple and easy to operate, has good repeatability, and is suitable for industrial production. DETAILED DESCRIPTION

[0029] The following examples further illustrate the application. EXAMPLE

[0030] In the following examples, boron phosphide is selected from Shaanxi Liedu New Material Co., Ltd., CAS No. 20205-91-8, wollastonite fiber is selected from Hubei Fengjiashan Silicon Fiber Co., Ltd., alkyl phosphate diethanolamine salt is selected from Haian County Huasi Surfactant Co., Ltd., and fatty alcohol polyoxyethylene ether phosphate is selected from Tiandao Biology, model number AEO-3P.

[0031] Example 1: A multi-layer coated ceramicized flame retardant, comprising the following weight percentage of raw materials: 3.5% alkyl phosphate diethanolamine salt, 24% wollastonite fiber, 72% boron phosphide and 0.5% fatty alcohol polyoxyethylene ether phosphate, wherein the aspect ratio of the wollastonite fiber is 20:1, and the diameter is 2 μm.

[0032] The preparation method of the above multi-layer coated ceramicized flame retardant comprises the following steps: (1) According to the raw material amount in Table 1, the alkyl phosphate diethanolamine salt is added to water, stirred at 95°C for 20 min to prepare a mixed solution, and the mass ratio of alkyl phosphate diethanolamine salt to water is 20:100; (2) The wollastonite fiber is added to the mixed solution obtained in step (1) and stirred at 95°C for 30 min to prepare a blended solution; (3) The blended solution obtained in step (2) is filtered, dried and ground to prepare a mixed powder, the drying temperature is 80°C, and the drying time is 10h; (4) The mixed powder obtained in step (3) is added to dipropylene glycol dimethyl ether, stirred at room temperature for 30 min, and then the fatty alcohol polyoxyethylene ether phosphate and boron phosphide are added and stirred uniformly, and then filtered, dried and crushed to prepare the multi-layer coated ceramicized flame retardant, the mass ratio of fatty alcohol polyoxyethylene ether phosphate to dipropylene glycol dimethyl ether is 2:100, the drying temperature is 90°C, the drying time is 8h, and the crushing particle size is 3 μm.

[0033] Table 1 Example 2: A multi-layer coated ceramifying flame retardant comprising the following raw materials by weight percentage: 2.75% alkyl phosphate diethanolamine salt, 16% wollastonite fiber, 81% boron phosphide, and 0.25% fatty alcohol polyoxyethylene ether phosphate, wherein the aspect ratio of the wollastonite fiber is 20:1 and the diameter is 2 μm.

[0034] The method for preparing the multi-layer coated ceramifying flame retardant described above comprises the following steps: (1) According to the raw material amount in Table 1, the alkyl phosphate diethanolamine salt is added to water, stirred at 90°C for 30 min to prepare a mixed solution, and the mass ratio of the alkyl phosphate diethanolamine salt to water is 30:100; (2) The wollastonite fiber is added to the mixed solution obtained in step (1) and stirred at 90°C for 40 min to prepare a blended solution; (3) The blended solution obtained in step (2) is filtered, dried, and ground to prepare a mixed powder, the drying temperature is 90°C, and the drying time is 8 h; (4) The mixed powder obtained in step (3) is added to dipropylene glycol dimethyl ether, stirred at room temperature for 40 min, and then the fatty alcohol polyoxyethylene ether phosphate and the boron phosphide are added and stirred uniformly, and then filtered, dried, and crushed to prepare the multi-layer coated ceramifying flame retardant, the mass ratio of the fatty alcohol polyoxyethylene ether phosphate to the dipropylene glycol dimethyl ether is 0.5:100, the drying temperature is 100°C, the drying time is 7 h, and the crushing particle size is 3 μm.

[0035] Example 3: A multi-layer coated ceramifying flame retardant comprising the following raw materials by weight percentage: 4.25% alkyl phosphate diethanolamine salt, 30% wollastonite fiber, 65% boron phosphide, and 0.75% fatty alcohol polyoxyethylene ether phosphate, wherein the aspect ratio of the wollastonite fiber is 20:1 and the diameter is 2 μm.

[0036] The method for preparing the multi-layer coated ceramifying flame retardant described above comprises the following steps: (1) According to the raw material amount in Table 1, the alkyl phosphate diethanolamine salt is added to water, stirred at 90°C for 30 min to prepare a mixed solution, and the mass ratio of the alkyl phosphate diethanolamine salt to water is 30:100; (2) The wollastonite fiber is added to the mixed solution obtained in step (1) and stirred at 90°C for 40 min to prepare a blended solution; (3) The blended solution obtained in step (2) is filtered, dried, and ground to prepare a mixed powder, the drying temperature is 90°C, and the drying time is 8 h; (4) The mixed powder obtained in step (3) is added to dipropylene glycol dimethyl ether, stirred at room temperature for 20 min, and then the fatty alcohol polyoxyethylene ether phosphate and boron phosphide are added after uniform stirring. After uniform stirring, filtration, drying, and crushing, a multi-layer coated ceramicized flame retardant is prepared. The mass ratio of the fatty alcohol polyoxyethylene ether phosphate and the dipropylene glycol dimethyl ether is 1:100, the drying temperature is 100°C, the drying time is 7 h, and the crushing is to a particle size of 3 μm.

[0037] Comparative Example Comparative Example 1: A multi-layer coated ceramicized flame retardant includes the following raw materials by weight percentage: 2% alkyl phosphate diethanolamine salt, 10% wollastonite fiber, 87% boron phosphide, and 1% fatty alcohol polyoxyethylene ether phosphate.

[0038] The preparation method of the multi-layer coated ceramicized flame retardant includes the following steps: (1) The alkyl phosphate diethanolamine salt is added to water according to the raw material amount in Table 2, stirred at 95°C for 20 min, and a mixed solution is prepared. The mass ratio of the alkyl phosphate diethanolamine salt and water is 20:100; (2) The wollastonite fiber is added to the mixed solution obtained in step (1), stirred at 95°C for 30 min, and a blended solution is prepared; (3) The blended solution obtained in step (2) is filtered, dried, and ground to prepare a mixed powder. The drying temperature is 80°C, and the drying time is 10 h; (4) The mixed powder obtained in step (3) is added to dipropylene glycol dimethyl ether, stirred at room temperature for 30 min, and then the fatty alcohol polyoxyethylene ether phosphate and boron phosphide are added after uniform stirring. After uniform stirring, filtration, drying, and crushing, a multi-layer coated ceramicized flame retardant is prepared. The mass ratio of the fatty alcohol polyoxyethylene ether phosphate and the dipropylene glycol dimethyl ether is 2:100, the drying temperature is 90°C, the drying time is 8 h, and the crushing is to a particle size of 3 μm.

[0039] Table 2 Comparative Example 2: A multi-layer coated ceramicized flame retardant includes the following raw materials by weight percentage: 4.9% alkyl phosphate diethanolamine salt, 40% wollastonite fiber, 55% boron phosphide, and 0.1% fatty alcohol polyoxyethylene ether phosphate.

[0040] The preparation method of the multi-layer coated ceramicized flame retardant includes the following steps: (1) The alkyl phosphate diethanolamine salt is added to water according to the raw material amount in Table 2, stirred at 95°C for 20 min, and a mixed solution is prepared. The mass ratio of the alkyl phosphate diethanolamine salt and water is 20:100; (2) Adding wollastonite fiber into the mixture obtained in step (1) and stirring at 95℃ for 30 min to obtain a blended solution; (3) Filtering, drying and grinding the blended solution obtained in step (2) to obtain a mixed powder, the drying temperature is 80℃ and the drying time is 10h; (4) Adding the mixed powder obtained in step (3) into dipropylene glycol dimethyl ether and stirring at room temperature for 30 min, then adding fatty alcohol polyoxyethylene ether phosphate and boron phosphide, and filtering, drying and crushing after uniform stirring to obtain a multi-layer coated ceramicized flame retardant, the mass ratio of fatty alcohol polyoxyethylene ether phosphate and dipropylene glycol dimethyl ether is 2:100, the drying temperature is 90℃, the drying time is 8h, and the crushing is to a particle size of 3μm.

[0041] Comparative Example 3: A multi-layer coated ceramicized flame retardant, which is different from Example 1 in that deionized water is used to replace fatty alcohol polyoxyethylene ether phosphate in an equal amount.

[0042] Comparative Example 4: A multi-layer coated ceramicized flame retardant, which is different from Example 1 in that an equal amount of deionized water is used to replace alkyl phosphate diethanolamine salt.

[0043] Comparative Example 5: A multi-layer coated ceramicized flame retardant, which is different from Example 1 in that an equal amount of wollastonite fiber is used to replace boron phosphide.

[0044] Comparative Example 6: A multi-layer coated ceramicized flame retardant, which is different from Example 1 in that an equal amount of white carbon black is used to replace wollastonite fiber and boron phosphide.

[0045] Comparative Example 7: A low-temperature ceramicizable silicone rubber, the component ratio of each raw material is: methyl vinyl silicone rubber 80%, fumed white carbon black 5%, halloysite 5%, glass powder 5%, boron nitride 3%, hydroxy silicone oil 1%, and DBPMH 1%.

[0046] The preparation method is as follows: first, boron nitride and glass powder with a softening point of 350℃ are stirred and mixed for 10 min, then sintered in a muffle furnace at 350℃ for 60 min, and cooled in the furnace, and the mixture is ground by a three-roll grinder for 10 min to prepare a composite fluxing agent with heat conduction function; then the silicone rubber, fumed white carbon black, hydroxy silicone oil, halloysite and composite fluxing agent are added into a rubber internal mixer and mixed at 50℃ for 30 min, then the curing agent DBPMH is added and mixed for 3 min to obtain a mixed rubber, which is stored for 12h and then returned to a rubber open mill for 3 min; the mixed rubber is vulcanized under the conditions of 150℃×15 min for the first stage and 180℃×2h for the second stage to obtain a ceramicized silicone rubber vulcanizate.

[0047] Application Example Application Example 1: A wire and cable material, comprising the following raw materials by weight: 100 kg of ethylene-propylene rubber, 200 kg of the multi-layer coated ceramifying flame retardant and 1.5 kg of DCP, the ethylene-propylene rubber is a terpolymer ethylene-propylene rubber, the ethylene content is 65%, the Mooney value is 66, the third monomer content is 4, selected from Shanghai Panren International Trade Co., Ltd., the model is 512F, the multi-layer coated ceramifying flame retardant is prepared by Example 1; the preparation method of the above wire and cable is as follows: the terpolymer ethylene-propylene rubber, the multi-layer coated ceramifying flame retardant and the DCP are mixed and put into the internal mixer, and then uniformly mixed at 180℃, each mixing time is 15 min, mixing for 2 times, extruded and granulated to prepare the wire and cable material.

[0048] Application Example 2: A wire and cable material, which is different from Application Example 1 in that the multi-layer coated ceramifying flame retardant is prepared by Example 2.

[0049] Application Example 3: A wire and cable material, which is different from Application Example 1 in that the multi-layer coated ceramifying flame retardant is prepared by Example 3.

[0050] Application Example 4: A wire and cable material, which is different from Application Example 1 in that the multi-layer coated ceramifying flame retardant is prepared by Comparative Example 1.

[0051] Application Example 5: A wire and cable material, which is different from Application Example 1 in that the multi-layer coated ceramifying flame retardant is prepared by Comparative Example 2.

[0052] Application Example 6: A wire and cable material, which is different from Application Example 1 in that the multi-layer coated ceramifying flame retardant is prepared by Comparative Example 3.

[0053] Application Example 7: A wire and cable material, which is different from Application Example 1 in that the multi-layer coated ceramifying flame retardant is prepared by Comparative Example 4.

[0054] Application Example 8: A wire and cable material, which is different from Application Example 1 in that the multi-layer coated ceramifying flame retardant is prepared by Comparative Example 5.

[0055] Application Example 9: A wire and cable material, which is different from Application Example 1 in that the multi-layer coated ceramifying flame retardant is prepared by Comparative Example 6.

[0056] Application Example 10: A wire and cable material, which is different from Application Example 1 in that the multi-layer coated ceramifying flame retardant is prepared by Comparative Example 7.

[0057] Performance detection test The flame-retardant powder is prepared according to the method in the examples and comparative examples, and the performance detection is carried out according to the following method, and the detection results are recorded in Table 3.

[0058] 1. Tensile strength: detected according to GB / T 528-2009 “Determination of tensile stress-strain properties of vulcanized or thermoplastic rubber”; 2. Elongation at break: tested according to GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized or thermoplastic rubbers"; 3. Bending strength of ceramic body: tested according to GB / T 6569-2006 "Fine ceramic - Bending strength test method", sintering temperature is 400℃, sintering time is 45min; 4. Integrity of ceramic body: 1500℃ flame burning for 30min; 5. Oxygen index: tested according to GB / T 2406.2-2009 "Determination of the ignition behavior of plastics - Part 2: Burning in a specified atmosphere: determination of the ignition time in a room"; 6. Smoke density: tested according to GB / T 8323.2-2008 "Determination of the smoke density of plastics - Part 2: Test method using a single-chamber method"; 7. Vertical burning performance: tested according to GB / T 2408-2008 "Determination of the burning behavior of plastics - Horizontal and vertical method".

[0059] Table 3 As can be seen from the data in Table 3, the tensile strength of the wire and cable material prepared by using the multilayer coated ceramic flame retardant prepared in application examples 1-3 reaches more than 12MPa, the elongation is more than 250%, the oxygen index is higher than 30%, the smoke density is less than 200%, and the vertical burning grade is V1 level. It can be seen that the multilayer coated ceramic flame retardant can better improve the mechanical strength and flame retardance of the wire and cable material, and can form a ceramic body at a lower temperature during burning, and the ceramic body has good integrity and high density, which can further improve the flame retardant effect.

[0060] In application example 4 and application example 5, the multilayer coated ceramic flame retardant prepared by using comparative example 1 and comparative example 2 respectively, the raw material ratio of the multilayer coated ceramic flame retardant is changed. Compared with application example 1, the tensile strength and elongation at break of the wire and cable material prepared in application example 4 are reduced, the bending strength of the ceramic body is weakened, and the oxygen index is decreased and the smoke density is increased after burning at 1500℃ for 30min.

[0061] In application example 6 and application example 7, the multilayer coated ceramic flame retardant is prepared by using comparative example 3 and comparative example 4 respectively. In comparative example 3 and comparative example 4, no fatty alcohol polyoxyethylene ether phosphate and alkyl phosphate diethanolamine salt is added. As shown in Table 3, the tensile strength and elongation at break of the wire and cable material prepared in application example 6 and application example 7 are significantly weakened, the bending strength of the ceramic body is significantly decreased, and the oxygen index is decreased.

[0062] The multilayer coated ceramic flame retardant prepared in application example 8 is made of the comparative example 5, and the multilayer coated ceramic flame retardant prepared in application example 9 is made of the comparative example 6. The comparative example 5 uses wollastonite fiber instead of boron phosphide, and the comparative example 6 only uses white carbon black instead of wollastonite fiber and boron phosphide. As shown in Table 3, the strength of the ceramic body and the oxygen index of the wire and cable material prepared in application example 8 and application example 9 decrease after burning, and the flame retardant effect is weakened.

[0063] The ceramic body prepared in application example 10 is ceramicizable silicone rubber prepared by the prior art. The ceramic body is cracked after being burned at 1500℃ for 30min, the heat resistance of the ceramic body is poor, and the bending strength of the ceramic body is small.

[0064] The specific embodiments are only an explanation of the present application, and are not a limitation of the present application. Those skilled in the art can make modifications to the embodiments without creative contribution after reading the present specification, and the modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A method for preparing a multilayer coated ceramic flame retardant, characterized in that: Includes the following steps: (1) Add alkyl phosphate diethanolamine salt to water and stir until homogeneous to obtain a mixture; (2) Add wollastonite fibers to the mixture and stir evenly to obtain a blend; (3) The blended liquid is filtered, dried and ground to obtain a mixed powder; (4) The mixed powder is added to dipropylene glycol dimethyl ether, stirred evenly, and then fatty alcohol polyoxyethylene ether phosphate and boron phosphide are added. After stirring evenly, the mixture is filtered, dried, and pulverized to prepare a multi-layer coated ceramic flame retardant.

2. The preparation method of the multilayer coated ceramic flame retardant according to claim 1, characterized in that: The mass ratio of the alkyl phosphate diethanolamine salt to water is 20-30:

100.

3. The preparation method of the multilayer coated ceramic flame retardant according to claim 1, characterized in that: The mass ratio of fatty alcohol polyoxyethylene ether phosphate to dipropylene glycol dimethyl ether is 100:0.5-2.

4. The preparation method of the multilayer coated ceramic flame retardant according to claim 1, characterized in that: In step (1), the stirring temperature is 90-100℃ and the stirring time is 10-30min.

5. The preparation method of the multilayer coated ceramic flame retardant according to claim 1, characterized in that: In step (2), the stirring temperature is 90-100℃ and the stirring time is 20-40min.

6. A multi-layer coated ceramic flame retardant, characterized in that, Made by the preparation method according to any one of claims 1-5, comprising the following raw materials by weight percentage: 16-30% wollastonite fiber, 65-81% boron phosphide, 2.75-4.25% alkyl phosphate diethanolamine salt, and 0.25-0.75% fatty alcohol polyoxyethylene ether phosphate.

7. The multilayer coated ceramic flame retardant according to claim 6, characterized in that: The raw materials include the following weight percentages: 24% wollastonite fiber, 72% boron phosphide, 3.5% alkyl phosphate diethanolamine salt and 0.5% fatty alcohol polyoxyethylene ether phosphate.

8. The multilayer coated ceramic flame retardant according to claim 6, characterized in that: The aspect ratio of the wollastonite fibers is 2-20:

1.

9. The application of the multilayer coated ceramic flame retardant prepared by the preparation method of any one of claims 1-5 in wire and cable materials, characterized in that, The wire and cable material comprises the following raw materials in parts by weight: 100 parts of ethylene propylene rubber, 150-300 parts of multi-layer coated ceramic flame retardant, and 1-3 parts of DCP.

10. The application of the multilayer coated ceramic flame retardant according to claim 9 in wires and cables, characterized in that: The ethylene propylene rubber is a ternary ethylene propylene rubber with an ethylene content of 58-66%.

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